Fuel cells are typically in the form of stacks of plates sandwiched between a pair of end plates. In a typical fuel cell, hydrogen or a hydrogen-rich gas stream is fed to the fuel cell anode and oxygen or air is fed to the fuel cell cathode. Prior to being introduced to the fuel cell stack these reactants are preferably cooled or heated to the fuel cell operating temperature by one or more heat exchangers. The heat exchangers and the fuel cell stack are typically separate components connected together by conduits. The use of separately formed heat exchangers can be problematic where space is limited and may add to complication and cost of the fuel cell system.
The fuel cell stack must be maintained within a narrow temperature range in order to operate efficiently. The end plates, however, are in contact with both the ambient surroundings and with the fuel cell plates at the top and bottom of the fuel cell stack. Thus, the fuel cell plates which are in close proximity to the end plates can be at a temperature which is different from the optimum temperature of the central portions of the stack, resulting in lost efficiency.